Motor interface for parallel drive shafts within an independently rotating member

ABSTRACT

Mechanisms, assemblies, systems, tools, and methods incorporating the use of an offset drive shaft within an independently rotating member are provided. An example mechanism includes a base and a main shaft mounted to rotate relative to the base, a first drive shaft mounted inside the main shaft, and a first drive feature engaged with the first drive shaft. The main shaft includes a proximal end, a distal end, and a main shaft rotational axis defined therebetween. The first drive shaft is offset from the main shaft rotational axis. A first drive feature rotational axis is defined for the first drive feature and is fixed relative to the base as the main shaft rotates. The first drive feature rotates the first drive shaft.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.12/945,461, filed Nov. 12, 2010, which claims the benefit under 35U.S.C. §119(e) of U.S. Provisional Application No. 61/260,919, filedNov. 13, 2009; both of which are incorporated herein by reference. Thisapplication is also related to U.S. application Ser. No. 12/945,730,filed Nov. 12, 2010; U.S. application Ser. No. 12/945,740, filed Nov.12, 2010; U.S. application Ser. No. 12/945,748, filed Nov. 12, 2010; andU.S. application Ser. No. 12/945,541, filed on Nov. 12, 2010; the fulldisclosures of which are incorporated herein by reference.

BACKGROUND

Minimally invasive surgical techniques are aimed at reducing the amountof extraneous tissue that is damaged during diagnostic or surgicalprocedures, thereby reducing patient recovery time, discomfort, anddeleterious side effects. As a consequence, the average length of ahospital stay for standard surgery may be shortened significantly usingminimally invasive surgical techniques. Also, patient recovery times,patient discomfort, surgical side effects, and time away from work mayalso be reduced with minimally invasive surgery.

A common form of minimally invasive surgery is endoscopy, and a commonform of endoscopy is laparoscopy, which is minimally invasive inspectionand surgery inside the abdominal cavity. In standard laparoscopicsurgery, a patient's abdomen is insufflated with gas, and cannulasleeves are passed through small (approximately one-half inch or less)incisions to provide entry ports for laparoscopic instruments.

Laparoscopic surgical instruments generally include an endoscope (e.g.,laparoscope) for viewing the surgical field and tools for working at thesurgical site. The working tools are typically similar to those used inconventional (open) surgery, except that the working end or end effectorof each tool is separated from its handle by an extension tube (alsoknown as, e.g., an instrument shaft or a main shaft). The end effectorcan include, for example, a clamp, grasper, scissor, stapler, cauterytool, linear cutter, or needle holder.

To perform surgical procedures, the surgeon passes working tools throughcannula sleeves to an internal surgical site and manipulates them fromoutside the abdomen. The surgeon views the procedure from a monitor thatdisplays an image of the surgical site taken from the endoscope. Similarendoscopic techniques are employed in, for example, arthroscopy,retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy,sinoscopy, hysteroscopy, urethroscopy, and the like.

Minimally invasive telesurgical robotic systems are being developed toincrease a surgeon's dexterity when working on an internal surgicalsite, as well as to allow a surgeon to operate on a patient from aremote location (outside the sterile field). In a telesurgery system,the surgeon is often provided with an image of the surgical site at acontrol console. While viewing a three dimensional image of the surgicalsite on a suitable viewer or display, the surgeon performs the surgicalprocedures on the patient by manipulating master input or controldevices of the control console. Each of the master input devicescontrols the motion of a servo-mechanically actuated/articulatedsurgical instrument. During the surgical procedure, the telesurgicalsystem can provide mechanical actuation and control of a variety ofsurgical instruments or tools having end effectors that perform variousfunctions for the surgeon, for example, holding or driving a needle,grasping a blood vessel, dissecting tissue, or the like, in response tomanipulation of the master input devices.

Manipulation and control of these end effectors is a particularlybeneficial aspect of robotic surgical systems. For this reason, it isdesirable to provide surgical tools that include mechanisms that providethree degrees of rotational movement of an end effector to mimic thenatural action of a surgeon's wrist. Such mechanisms should beappropriately sized for use in a minimally invasive procedure andrelatively simple in design to reduce possible points of failure. Inaddition, such mechanisms should provide an adequate range of motion toallow the end effector to be manipulated in a wide variety of positions.

Non robotic linear clamping, cutting and stapling devices have beenemployed in many different surgical procedures. For example, such adevice can be used to resect a cancerous or anomalous tissue from agastro-intestinal tract. Unfortunately, many known surgical devices,including known linear clamping, cutting and stapling devices, oftenhave opposing jaws that may be difficult to maneuver within a patient.For known devices having opposing jaws that are maneuverable within apatient, such devices may not generate sufficient clamping force forsome surgical applications (e.g., tissue clamping, tissue stapling,tissue cutting, etc.), which may reduce the effectiveness of thesurgical device.

Thus, there is believed to be a need for an improvement in themaneuverability of surgical end effectors, particularly with regard tominimally invasive surgery. In addition, there is believed to be a needfor surgical end effectors with high actuation force, for example, highclamping force.

BRIEF SUMMARY

Mechanisms, assemblies, systems, tools, and methods are provided, manyof which incorporate the use of an offset drive shaft within anindependently rotating member. Such mechanisms, assemblies, systems,tools, and methods may be particularly beneficial for use in surgery,for example, in minimally invasive surgery, in minimally invasiverobotic surgery, as well as other types of surgery. The combination ofan offset drive shaft mounted for rotation within an independentlyrotatable instrument shaft allows significant actuation power to betransferred to an end effector while leaving a central region of theinstrument shaft available for routing of other components, for example,control cables, control wires, catheters, or other such components.Drive shaft actuation can be used to articulate and/or orient an endeffector, for example, so as to provide a relatively high desiredclamping force, such as for cutting or stapling, optionally with alimited response rate. Cable actuation may be used for relatively lowerforce articulation and/or orientation of the end effector when a higherresponse rate is desired, such as when telesurgically grasping andmanipulating tissues. Exemplary hybrid cable/shaft actuated systems mayselectably actuate a single grasping/treatment jaw joint using either ahigh force shaft drive or a high response cable drive. While the variousembodiments disclosed herein are primarily described with regard tosurgical applications, related mechanisms, assemblies, systems, tools,and methods may find use in a wide variety of applications, both insideand outside a human body, as well as in non-surgical applications.

In a first aspect, a mechanism including an offset drive shaft mountedwithin a rotating main shaft is provided. The mechanism includes a base,a main shaft mounted to rotate relative to the base, a first drive shaftmounted inside the main shaft, and a first drive feature engaged withthe first drive shaft. The main shaft includes a proximal end, a distalend, and a main shaft rotational axis defined therebetween. The firstdrive shaft is offset from the main shaft rotational axis. A first drivefeature rotational axis is defined for the first drive feature and isfixed relative to the base as the main shaft rotates. The first drivefeature rotates the first drive shaft.

Various approaches may used to rotate the first drive shaft via thefirst drive feature. For example, the main shaft rotational axis and thefirst drive feature rotational axis can be coincident. Engagementbetween the first drive feature and the first drive shaft can permit anaxial movement of the first drive shaft relative to the base. The firstdrive feature can be engaged with the first drive shaft through anopening in the main shaft. The first drive shaft can include a seconddrive feature that protrudes through the main shaft opening and engagesthe first drive feature. The second drive feature can include externalgear teeth. The first drive feature can include an internal ring gear.

In many embodiments, the mechanism includes a third drive feature forrotating the main shaft. For example, a third drive feature having athird drive feature rotational axis can engage the main shaft. The thirddrive feature rotational axis can be fixed relative to the base as thethird drive feature rotates the main shaft.

In many embodiments, a second drive shaft is mounted inside the mainshaft and offset from the main shaft rotational axis. A fourth drivefeature having a fourth drive feature rotational axis can be engagedwith the second drive shaft. A fourth drive feature rotational axis canbe fixed relative to the base as the main shaft rotates. The fourthdrive feature can rotate the second drive shaft. The fourth drivefeature can be engaged with the second drive shaft through an opening inthe main shaft.

In many embodiments, the support of the first drive shaft is integratedinto the main shaft. For example, the main shaft can include a recessconfigured to interface with a bearing supporting the first drive shaft,and the mechanism can further include the bearing supporting the firstdrive shaft. The mechanism can further include a retaining ring toretain the bearing supporting the first drive shaft.

In many embodiments, an end effector is coupled with the distal end ofthe main shaft. The end effector can be coupled with the first driveshaft and/or with the second drive shaft. The end effector can berotated by a rotation of the main shaft. A rotation of the first driveshaft and/or of the second drive shaft can actuate the end effector.

In many embodiments, the mechanism further comprises a control cabledrive feature and a control cable engaged with the control cable drivefeature. The control cable can be routed within the main shaft betweenthe main shaft proximal and distal ends. The mechanism can furthercomprise an end effector coupled with the control cable. A motion of thecontrol cable can actuate the end effector.

In another aspect, a robotic assembly including an offset drive shaftmounted within a rotating main shaft is provided. The robotic assemblyincludes a base; a main shaft mounted to rotate relative to the base; adrive shaft mounted inside the main shaft; an actuation assembly coupledwith the main shaft and the drive shaft; and an end effector coupledwith the main shaft. The main shaft includes a proximal end, a distalend, and a main shaft rotational axis defined therebetween. The driveshaft is offset from the main shaft rotational axis. The actuationassembly is operable to independently rotate the main shaft relative tothe base, and rotate the drive shaft relative to the main shaft. The endeffector includes a shaft driven mechanism coupled with the drive shaft.

In many embodiments, the robotic assembly further comprises a seconddrive shaft mounted inside the main shaft and offset from the main shaftrotational axis. The actuation assembly can be further operable toindependently rotate the second drive shaft relative to the main shaft.The end effector can further comprise a second shaft driven actuationmechanism operatively coupled with the second drive shaft.

In many embodiments, the robotic assembly further comprises a controlcable coupled with the end effector. The control cable can be routedwithin the main shaft between the main shaft proximal and distal ends. Amotion of the control cable can actuate the end effector.

In another aspect, a robotic system including an offset drive shaftmounted within a rotating main shaft is provided. The robotic systemincludes a base; a main shaft mounted to rotate relative to the base; afirst drive shaft mounted inside the main shaft; a second drive shaftmounted inside the main shaft; an actuation assembly coupled with themain shaft, the first drive shaft, and the second drive shaft; acontroller; and an end effector coupled with the main shaft so that theend effector is rotated by a rotation of the main shaft. The main shaftincludes a proximal end, a distal end, and a main shaft rotational axisdefined therebetween. The first drive shaft and the second drive shaftare offset from the main shaft rotational axis. The controller includesan input and an output. The input is coupled with an input device toreceive at least one input signal from the input device. The output iscoupled with the actuation assembly to output at least one controlsignal to the actuation assembly. The controller includes a processorand a tangible medium containing instructions that when executed causethe processor to generate the at least one control signal in response tothe at least one input signal so that the input device can be used by auser to independently rotate the main shaft relative to the base, rotatethe first drive shaft relative to the main shaft, and rotate the seconddrive shaft relative to the main shaft. The end effector includes afirst shaft driven mechanism coupled with the first drive shaft and asecond shaft driven actuation mechanism coupled with the second driveshaft.

In many embodiments, the actuation assembly comprises additionalcomponents. For example, the actuation assembly can include a firstmotor coupled with the first drive shaft and the controller. Theactuation assembly can include a second motor coupled with the seconddrive shaft and the controller. The actuation assembly can include amain shaft motor coupled with the main shaft and the controller. Theactuation assembly can include a first encoder coupled with the firstmotor and the controller. The first encoder can output a first motorposition signal to the controller in response to a position of the firstmotor. The actuation assembly can include a second encoder coupled withthe second motor and the controller. The second encoder can output asecond motor position signal to the controller in response to a positionof the second motor. The actuation assembly can include a main shaftencoder coupled with the main shaft motor and the controller. The mainshaft encoder can output a main shaft position signal to the controllerin response to a position of the main shaft motor.

In many embodiments, the robotic system further comprises a controlcable coupled with the end effector. The control cable can be routedwithin the main shaft between the main shaft proximal and distal ends. Amotion of the control cable can actuate the end effector.

In another aspect, a robotic tool including an offset drive shaftmounted within a rotating main shaft is provided. The robotic tool isconfigured for mounting on a manipulator having a tool interface withfirst, second, and third drive features. The robotic tool includes aproximal tool chassis releasably mountable to the tool interface; adistal end effector having a distal degree of freedom and a shaft drivenactuation mechanism; a main shaft having a proximal end adjacent thechassis, a distal end adjacent the end effector, a bore extendingtherebetween, and a lateral opening distally of the proximal end; and ahybrid cable/shaft drive system operatively coupling the drive featuresof the tool interface to the end effector when the chassis is mounted tothe tool interface. Actuation of the first drive feature rotates themain shaft and the end effector relative to the chassis about a mainshaft rotational axis. Cables extending from the chassis distally withinthe bore of the main shaft couple the distal degree of freedom of theend effector to the second drive feature. The first drive shaft couplesthe shaft driven actuation mechanism of the end effector to the thirddrive feature through the lateral opening in the main shaft. The firstdrive shaft is offset from the main shaft rotational axis.

In another aspect, a method for transmitting torque through an offsetdrive shaft routed within a rotatable main shaft is provided. The methodincludes supporting a main shaft to rotate relative to a base so thatthe main shaft rotates about a main shaft rotational axis, supporting adrive shaft to rotate relative to the main shaft so that the drive shaftrotates about a drive shaft rotational axis that is offset from the mainshaft rotational axis, engaging the drive shaft with a drive featurehaving a drive feature rotational axis that is fixed relative to thebase as the main shaft rotates, rotating the main shaft relative to thebase, and rotating the drive feature relative to the main shaft so as torotate the drive shaft relative to the main shaft. In many embodiments,the main shaft rotates relative to the base and the drive shaft rotatesrelative to the main shaft simultaneously.

In another aspect, a minimally invasive surgical method is provided. Themethod includes introducing an end effector to an internal surgical sitewithin a patient through a minimally invasive aperture or naturalorifice by manipulating a base, rotating the end effector relative tothe base, and performing a surgical task with the end effector byrotating a first drive shaft relative to the instrument shaft so thatthe first drive shaft actuates the end effector. In the method, the endeffector is supported relative to the base by an elongated instrumentshaft, the end effector is rotated relative to the base by rotating theinstrument shaft relative to the base about an instrument shaftrotational axis, and the first drive shaft rotates relative to theinstrument shaft about a first drive shaft rotational axis that isoffset from the instrument shaft rotational axis. In many embodiments,the method further comprises actuating the end effector by rotating asecond drive shaft relative to the instrument shaft, the second driveshaft rotating about a second drive shaft rotational axis that is offsetfrom the instrument shaft rotational axis.

For a fuller understanding of the nature and advantages of the presentinvention, reference should be made to the ensuing detailed descriptionand accompanying drawings. Other aspects, objects and advantages of theinvention will be apparent from the drawings and detailed descriptionthat follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a minimally invasive robotic surgery systembeing used to perform a surgery, in accordance with many embodiments.

FIG. 2 is a perspective view of a surgeon's control console for arobotic surgery system, in accordance with many embodiments.

FIG. 3 is a perspective view of a robotic surgery system electronicscart, in accordance with many embodiments.

FIG. 4 diagrammatically illustrates a robotic surgery system, inaccordance with many embodiments.

FIG. 5A is a front view of a patient side cart (surgical robot) of arobotic surgery system, in accordance with many embodiments.

FIG. 5B is a front view of a robotic surgery tool.

FIG. 6 diagrammatically illustrates a robotic assembly having two offsetdrive shafts within a rotatable main shaft, in accordance with manyembodiments.

FIG. 7 diagrammatically illustrates the integration of components of therobotic assembly of FIG. 6 with a controller, in accordance with manyembodiments.

FIG. 8 diagrammatically illustrates a robotic tool and an associatedrobotic system, in accordance with many embodiments.

FIG. 9 is a perspective view of a robotic tool that is releasablymountable to a robotic tool manipulator, in accordance with manyembodiments.

FIG. 10 is a perspective view of the proximal end of a robotic tool ofFIG. 9, showing an actuation assembly, in accordance with manyembodiments.

FIG. 11 is a perspective view of a cross section of the actuationassembly of FIG. 10, illustrating components used to actuate a firstoffset internal drive shaft, in accordance with many embodiments.

FIG. 12 is a perspective view illustrating components of the actuationassembly of FIG. 10 that are used to actuate a second offset internaldrive shaft, in accordance with many embodiments.

FIG. 13 is a perspective view of a cross section of the actuationassembly of FIG. 10, illustrating various components and the routing ofend effector control cables, in accordance with many embodiments.

FIG. 14 is a cross-sectional view of the actuation assembly of FIG. 10,illustrating various components and the routing of end effector controlcables, in accordance with many embodiments.

FIG. 15A is a perspective view of a main shaft coupling fitting used tocouple a rotatable main shaft with a proximal tool chassis, showingopenings through which internally mounted offset drive shafts are drivenand external gear teeth that are used to rotate the main shaft, inaccordance with many embodiments.

FIG. 15B is a perspective view of an internal subassembly that includestwo internal offset drive shafts and associated support fittings, inaccordance with many embodiments.

FIG. 15C is a perspective view showing the combination of the componentsof FIGS. 15A and 15B, in accordance with many embodiments.

FIG. 15D is an end view showing the combination of the components ofFIGS. 15A and 15B, in accordance with many embodiments.

FIG. 16 is a perspective view of an actuation assembly having a reducedpart count configuration, in accordance with many embodiments.

FIG. 17 is a perspective cross-sectional view of the actuation assemblyof FIG. 16.

FIGS. 18A and 18B are proximal and distal end views, respectively, ofthe actuation assembly of FIG. 16.

FIG. 19 is a plan view illustration of the integration of the actuationassembly of FIG. 16 within a proximal tool chassis, in accordance withmany embodiments.

FIG. 20 is a simplified diagrammatic illustration of a surgicalassembly, in accordance with many embodiments.

FIG. 21 is a flow diagram of a method for transmitting torque through anoffset drive shaft routed within a rotatable main shaft, in accordancewith many embodiments.

FIG. 22 is a flow diagram of a minimally invasive surgical method, inaccordance with many embodiments.

DETAILED DESCRIPTION

Mechanisms, assemblies, systems, tools, and methods incorporating theuse of an offset drive shaft within an independently rotating member areprovided. Such mechanisms, assemblies, systems, tools, and methods maybe particularly beneficial for use in surgery, for example, in minimallyinvasive surgery, minimally invasive robotic surgery, as well as othertypes of surgery. While the various embodiments disclosed herein areprimarily described with regard to surgical applications, relatedmechanisms, assemblies, systems, tools, and methods can be used in awide variety of applications, both inside and outside a human body, aswell as in non-surgical applications.

Minimally Invasive Robotic Surgery

Referring now to the drawings, in which like reference numeralsrepresent like parts throughout the several views, FIG. 1 is a plan viewillustration of a Minimally Invasive Robotic Surgical (MIRS) system 10,typically used for performing a minimally invasive diagnostic orsurgical procedure on a Patient 12 who is lying down on an Operatingtable 14. The system can include a Surgeon's Console 16 for use by aSurgeon 18 during the procedure. One or more Assistants 20 may alsoparticipate in the procedure. The MIRS system 10 can further include aPatient Side Cart 22 (surgical robot), and an Electronics Cart 24. ThePatient Side Cart 22 can manipulate at least one removably coupled toolassembly 26 (hereinafter simply referred to as a “tool”) through aminimally invasive incision in the body of the Patient 12 while theSurgeon 18 views the surgical site through the Console 16. An image ofthe surgical site can be obtained by an endoscope 28, such as astereoscopic endoscope, which can be manipulated by the Patient SideCart 22 so as to orient the endoscope 28. The Electronics Cart 24 can beused to process the images of the surgical site for subsequent displayto the Surgeon 18 through the Surgeon's Console 16. The number ofsurgical tools 26 used at one time will generally depend on thediagnostic or surgical procedure and the space constraints within theoperating room among other factors. If it is necessary to change one ormore of the tools 26 being used during a procedure, an Assistant 20 mayremove the tool 26 from the Patient Side Cart 22, and replace it withanother tool 26 from a tray 30 in the operating room.

FIG. 2 is a perspective view of the Surgeon's Console 16. The Surgeon'sConsole 16 includes a left eye display 32 and a right eye display 34 forpresenting the Surgeon 18 with a coordinated stereo view of the surgicalsite that enables depth perception. The Console 16 further includes oneor more input control devices 36, which in turn cause the Patient SideCart 22 (shown in FIG. 1) to manipulate one or more tools. The inputcontrol devices 36 will provide the same degrees of freedom as theirassociated tools 26 (shown in FIG. 1) so as to provide the Surgeon withtelepresence, or the perception that the input control devices 36 areintegral with the tools 26 so that the Surgeon has a strong sense ofdirectly controlling the tools 26. To this end, position, force, andtactile feedback sensors (not shown) may be employed to transmitposition, force, and tactile sensations from the tools 26 back to theSurgeon's hands through the input control devices 36.

The Surgeon's Console 16 is usually located in the same room as thepatient so that the Surgeon may directly monitor the procedure, bephysically present if necessary, and speak to an Assistant directlyrather than over the telephone or other communication medium. However,the Surgeon can be located in a different room, a completely differentbuilding, or other remote location from the Patient allowing for remotesurgical procedures (i.e., operating from outside the sterile field).

FIG. 3 is a perspective view of the Electronics Cart 24. The ElectronicsCart 24 can be coupled with the endoscope 28 and can include a processorto process captured images for subsequent display, such as to a Surgeonon the Surgeon's Console, or on another suitable display located locallyand/or remotely. For example, where a stereoscopic endoscope is used,the Electronics Cart 24 can process the captured images so as to presentthe Surgeon with coordinated stereo images of the surgical site. Suchcoordination can include alignment between the opposing images and caninclude adjusting the stereo working distance of the stereoscopicendoscope. As another example, image processing can include the use ofpreviously determined camera calibration parameters so as to compensatefor imaging errors of the image capture device, such as opticalaberrations.

FIG. 4 diagrammatically illustrates a robotic surgery system 50 (such asMIRS system 10 of FIG. 1). As discussed above, a Surgeon's Console 52(such as Surgeon's Console 16 in FIG. 1) can be used by a Surgeon tocontrol a Patient Side Cart (Surgical Robot) 54 (such as Patent SideCart 22 in FIG. 1) during a minimally invasive procedure. The PatientSide Cart 54 can use an imaging device, such as a stereoscopicendoscope, to capture images of the procedure site and output thecaptured images to an Electronics Cart 56 (such as the Electronics Cart24 in FIG. 1). As discussed above, the Electronics Cart 56 can processthe captured images in a variety of ways prior to any subsequentdisplay. For example, the Electronics Cart 56 can overlay the capturedimages with a virtual control interface prior to displaying the combinedimages to the Surgeon via the Surgeon's Console 52. The Patient SideCart 54 can output the captured images for processing outside theElectronics Cart 56. For example, the Patient Side Cart 54 can outputthe captured images to a processor 58, which can be used to process thecaptured images. The images can also be processed by a combination theElectronics Cart 56 and the processor 58, which can be coupled togetherso as to process the captured images jointly, sequentially, and/orcombinations thereof. One or more separate displays 60 can also becoupled with the processor 58 and/or the Electronics Cart 56 for localand/or remote display of images, such as images of the procedure site,or other related images.

FIGS. 5A and 5B show a Patient Side Cart 22 and a surgical tool 62,respectively. The surgical tool 62 is an example of the surgical tools26. The Patient Side Cart 22 shown provides for the manipulation ofthree surgical tools 26 and an imaging device 28, such as a stereoscopicendoscope used for the capture of images of the site of the procedure.Manipulation is provided by robotic mechanisms having a number ofrobotic joints. The imaging device 28 and the surgical tools 26 can bepositioned and manipulated through incisions in the patient so that akinematic remote center is maintained at the incision so as to minimizethe size of the incision. Images of the surgical site can include imagesof the distal ends of the surgical tools 26 when they are positionedwithin the field-of-view of the imaging device 28.

Offset Drive Shaft(s) within a Rotatable Shaft

FIG. 6 diagrammatically illustrates a robotic assembly 70 having twooffset drive shafts within a rotatable main shaft, in accordance withmany embodiments. The robotic assembly 70 includes an end effector 72that is coupled with the distal end of a rotatable main shaft 74, and anactuation assembly 76 coupled with both the main shaft 74 and the endeffector 72.

The end effector 72 includes an end effector base, a first actuationmechanism 78, a second actuation mechanism 80, and a control cablemechanism(s) 82. The end effector base is pivotally coupled to therotatable main shaft 74. The first actuation mechanism 78 and the secondactuation mechanism 80 are shaft driven and can be used to actuateand/or articulate a variety of end effector features and/or devices, forexample, a clamping feature, a movable cutting feature, a cutting andstapling device, or another suitable end effector feature and/or devicethat can be actuated and/or articulated with a shaft driven mechanism.The control cable mechanism(s) 82 can also be used to actuate and/orarticulate a variety of end effector features and/or devices,particularly those where a fast response is desired, for example, agrasping feature, a main shaft to end effector base wrist that is usedto articulate the end effector base relative to the main shaft, oranother suitable feature and/or device that can be actuated and/orarticulated via one or more control cables.

The end effector base is coupled with the rotatable main shaft 74 sothat a rotation of the main shaft 74 about a main shaft rotation axisproduces a corresponding rotation of the end effector base. As discussedabove, the ability to independently rotate the main shaft 74 providesincreased end effector maneuverability relative to a non rotating mainshaft, which may be beneficial during certain surgical procedures, forexample, during certain minimally invasive surgical procedures. The endeffector base can also be coupled with the rotatable main shaft 74 witha suitable wrist mechanism 84 that provides additional end effectormaneuverability.

Two drive shafts are used to drive the end effector shaft drivenactuation mechanisms. A first drive shaft 86 is mounted for rotationabout a first drive shaft rotational axis that is offset from the mainshaft rotation axis. The first drive shaft 86 is operatively coupledwith the first actuation mechanism 78. Likewise, a second drive shaft 88is mounted for rotation about a second drive shaft rotational axis thatis offset from the main shaft rotation axis. The second drive shaft 88is operatively coupled with the second actuation mechanism 80.

The actuation assembly 76 is coupled with the rotatable main shaft 74,the first drive shaft 86, the second drive shaft 88, and the controlcable mechanism(s) 82. The rotatable main shaft 74 is mounted forrotation relative to a base of the actuation assembly 76. The actuationassembly 76 is operable to produce rotation of the rotatable main shaft74 relative to the base. The actuation assembly 76 is also operable togenerate any combination of rotation of the rotatable main shaft 74relative to the base, rotation of the first drive shaft 86 relative tothe rotatable main shaft 74, and rotation of the second drive shaft 88relative to the rotatable main shaft 74. As such, the first actuationmechanism 78 and/or the second actuation mechanism 80 can be actuatedindependently and/or simultaneously with rotation of the rotatable mainshaft 74.

The actuation assembly 76 is configured to provide the above describedfunctionality in which the first drive shaft 86 and the second driveshaft 88 can be independently rotated relative to the rotatable mainshaft 74, even during rotation of the rotatable main shaft 74 relativeto the base. The actuation assembly 76 includes a main shaft motor 90coupled with a main shaft encoder 92 and a main shaft interface 94, afirst motor 96 coupled with a first encoder 98 and a first interface100, a second motor 102 coupled with a second encoder 104 and a secondinterface 106, and a control cable motor(s) 108 coupled with a controlcable encoder(s) 110 and a control cable interface(s) 112. The mainshaft interface 94 is coupled with the rotatable main shaft 74 so as totransfer rotational motion from the main shaft motor 90 to the rotatablemain shaft 74. The main shaft motor 90 can be fixedly coupled with thebase so that the transferred rotational motion results in rotation ofthe rotatable main shaft 74 relative to the base. The main shaft encoder92 measures the orientation of the main shaft motor 90, the main shaftinterface 94, and/or the rotatable main shaft 74 and can be coupled witha controller (not shown in FIG. 6) so as to provide the controller withthe measured orientation. The first interface 100 is coupled with thefirst drive shaft 86 so as to be operable to transfer rotational motionfrom the first motor 96 to the first drive shaft 86 during anyorientation and/or rotational motion of the rotatable main shaft 74. Thefirst encoder 98 measures the orientation of the first motor 96, thefirst interface 100, and/or the first drive shaft 86 and can be coupledwith the controller so as to provide the controller with the measuredorientation. The second interface 106 is coupled with the second driveshaft 88 so as to be operable to transfer rotational motion from thesecond motor 102 to the second drive shaft 88 during any orientationand/or rotational motion of the rotatable main shaft 74. The secondencoder 104 measures the orientation of the second motor 102, the secondinterface 106, and/or the second drive shaft 88 and can be coupled withthe controller so as to provide the controller with the measuredorientation. The control cable interface(s) 112 is coupled with controlcable(s) 114 that are operatively coupled with the control cablemechanism(s) 82. The control cable(s) 114 can be routed so as totolerate a range of rotational orientations of the rotatable main shaft74, for example, by being routed in the vicinity of the main shaftrotational axis to minimize changes in control cable length due torotation of the rotatable main shaft 74, and by being configured totolerate any twisting of control cable(s) and/or twisting betweencontrol cables that may result for some rotational orientations of themain shaft 74 (e.g., by having a construction that toleratescable-to-cable rubbing). The control cable encoder(s) 110 measures theorientation of the control cable motor(s) 108 and/or the control cableinterface(s) 112 and can be coupled with the controller so as to providethe controller with the measured orientation(s).

FIG. 7 is a simplified block diagram illustrating the integration ofcomponents of the robotic assembly 70 with a controller 116, inaccordance with many embodiments. The controller 116 includes at leastone processor 118, which communicates with a number of peripheraldevices via a bus subsystem 120. These peripheral devices typicallyinclude a storage subsystem 122.

The storage subsystem 122 maintains the basic programming and dataconstructs that provide the functionality of the controller 116.Software modules for implementing the robotic assembly functionalitydiscussed above are typically stored in the storage subsystem 122. Thestorage subsystem 122 typically includes a memory subsystem 124 and afile storage subsystem 126.

The memory subsystem 124 typically includes a number of memoriesincluding a main random access memory (RAM) 128 for storage ofinstructions and data during program execution and a read only memory(ROM) 130, in which fixed instructions are stored.

The file storage subsystem 126 provides persistent (non-volatile)storage for program and data files, and can include a hard drive, a diskdrive, or other non-volatile memory such as a flash memory. An inputdevice, for example a disk drive, can be used to input the softwaremodules discussed above. Alternatively, other known structures mayalternatively be used to input the software modules, for example, a USBport.

In this context, the term “bus subsystem” is used generically so as toinclude any mechanism for letting the various components and subsystemscommunicate with each other as intended. The bus subsystem 120 is shownschematically as a single bus, but a typical system has a number ofbuses such as a local bus and one or more expansion buses (e.g., ADB,SCSI, ISA, EISA, MCA, NuBus, or PCI), as well as serial and parallelports.

The controller 116 controls components of the robotic assembly 70 inresponse to assorted received signals, including signals from the inputcontrol device(s) 36 (shown in FIG. 2), as well as from the main shaftencoder 92, the first encoder 98, the second encoder 104, and thecontrol cable encoder(s) 110. The components controlled include the mainshaft motor 90, the first motor 96, the second motor 102, and thecontrol cable motor(s) 108. Additional components (not shown), such asdigital/analog converters can be used to interface components with thecontroller 116.

FIG. 8 is a simplified block diagram illustrating the integration of arobotic surgery tool 132 within a robotic surgery system, in accordancewith many embodiments. The tool 132 includes a proximal tool chassis 134configured to be releasably mountable on a manipulator 136 having a toolinterface configured to interface with the proximal tool chassis 134.The tool 132 further includes an elongate main shaft 74 that is mountedto rotate relative to the proximal tool chassis 134 when rotated by amain shaft motor, as discussed above. An end effector 140 is coupledwith a distal end of the main shaft 74 so as to rotate along with themain shaft. A main control system 142 is operatively coupled with themanipulator 136. An auxiliary control system 144 can also be operativelycoupled with the manipulator 136. The combination of the main controlsystem 142 and the auxiliary control system 144 can be used to controlall possible articulations of the tool 132 via the manipulator 136. Forexample, the auxiliary control system 144 can control the drive motorsfor first drive shaft rotation and second drive shaft rotation. The maincontrol system 142 can control a drive motor for main shaft rotation andone or more control cable drive motors. Such an auxiliary controller canbe used to supplement existing robotic surgery system configurations soas to allow the use of the presently disclosed robotic tools having oneor more offset drive shafts routed within an independently rotating mainshaft.

FIG. 9 is a perspective view of a robotic surgery tool 132, inaccordance with many embodiments. As discussed above, the tool 132includes a proximal tool chassis 134 configured to be releasablymountable on a tool manipulator 136. The rotatable main shaft 74 couplesthe end effector 140 with the proximal tool chassis 134.

FIG. 10 is a perspective view of the proximal tool chassis 134 of FIG. 9(without the cover), showing an actuation assembly 142, in accordancewith many embodiments. The actuation assembly 142 includes a first motor96 for actuating a first offset drive shaft and a second motor 102 foractuating a second offset drive shaft. The various encoders discussedabove (e.g., the main shaft encoder 92, the first encoder 98, the secondencoder 104, and the control cable encoder(s) 110) can be integratedwithin the actuation assembly 142. The first motor 96 is coupled with aset of electrical connection pins 144 configured to couple with a matingelectrical connector that is coupled with a controller for selectivelydriving the first motor 96. Likewise, the second motor 102 is coupledwith a set of electrical connection pins 146 configured to couple with amating electrical connector that is coupled with the controller forselectively driving the second motor 102.

FIG. 11 is a perspective view of a cross section of the actuationassembly 142 of FIG. 10, illustrating components used to actuate a firstoffset internal drive shaft, in accordance with many embodiments. Thefirst motor 96 is rotationally coupled with a first motor gear 148. Thefirst motor gear 148 engages and drives a first coupling shaft proximalgear 150, which drives a first coupling shaft 152. The coupling shaft152 in turn rotates a first coupling shaft distal gear 154. The firstcoupling shaft distal gear 154 engages a first annular gear 156, whichincludes both external gear teeth 158 that engage the first couplingshaft distal gear 154 and internal ring gear teeth 160. The firstannular gear 156 is mounted to rotate about the centerline of therotatable main shaft 74 via a first annular gear bearing 162. The firstdrive shaft 86 is mounted to rotate about a first drive shaft rotationaxis that is offset from the rotatable main shaft rotation axis. Thefirst drive shaft 86 is mounted to the main shaft via two first driveshaft support hearings 164. The first drive shaft 86 is coupled with afirst drive shaft gear 166, which includes external gear teeth thatprotrude from an opening in a main shaft coupling fitting 168 so as toengage the internal gear teeth 160 of the first annular gear 156. Inoperation, rotation of the first motor 96 rotates the first motor gear148, which rotates the first coupling shaft proximal gear 150, whichrotates the coupling shaft 152, which rotates the first coupling shaftdistal gear 154, which rotates the first annular gear 156, which rotatesthe first drive shaft gear 166, which rotates the first drive shaft 86relative to the main shaft 74.

In many embodiments, the actuation assembly 142 is designed toaccommodate a range of axial motion of the first drive shaft 86, forexample, by designing the first annular gear 156 and the opening in themain shaft coupling fitting 168 for a range of axial motion of the firstdrive shaft 86 (e.g., by increasing the dimension of the opening and theannular gear 156 in the direction of the axial motion of the first driveshaft 86 over a size sufficient to accommodate the protruding gear teethof the first drive shaft gear 166 thereby allowing the first drive shaftgear 166 to slide axially relative to the internal ring gear teeth ofthe first annular gear 156). Such axial motion of the first drive shaft86 may occur during articulation of an end effector base relative to themain shaft where the end effector base rotates about a wrist axis thatis offset from the centerline of the first drive shaft 86.

FIG. 11 also illustrates actuation components used to actuate the secondoffset internal drive shaft 88, in accordance with many embodiments. Thesecond drive shaft 88 is mounted to rotate about a second drive shaftrotation axis that is offset from the rotatable main shaft rotationaxis. The second drive shaft 88 is mounted to the main shaft via seconddrive shaft support hearings 170. The second drive shaft 88 is coupledwith a second drive shaft gear 172, which includes external gear teeththat protrude from an opening in a main shaft coupling fitting 168 so asto engage internal ring gear teeth of a second annular gear 174. Thesecond annular gear 174 is mounted to rotate about the centerline of therotatable main shaft 74 via a second annular gear bearing 175. Asdiscussed above with regard to the first drive shaft, the actuationassembly 142 can also be designed to accommodate a range of axial motionof the second drive shaft 88, for example, by designing the secondannular gear 174 and the opening in the main shaft coupling fitting 168for a range of axial motion of the second drive shaft 88.

FIG. 12 is a perspective view illustrating components of the actuationassembly 142 of FIG. 10 that are used to actuate a second offsetinternal drive shaft, in accordance with many embodiments. The secondmotor 102 is rotationally coupled with a second motor gear 176. Thesecond motor gear 176 engages and drives a second coupling shaftproximal gear 178, which drives a second coupling shaft 180. The secondcoupling shaft 180 in turn rotates a second coupling shaft distal gear182. The second coupling shaft distal gear 182 engages the secondannular gear 174, which includes both external gear teeth that engagethe second coupling shaft distal gear 182 and internal ring gear teeth.The second annular gear 174 is mounted to rotate about the centerline ofthe rotatable main shaft via a second annular gear bearing. Inoperation, rotation of the second motor 102 rotates the second motorgear 176, which rotates the second coupling shaft proximal gear 178,which rotates the second coupling shaft 180, which rotates the secondcoupling shaft distal gear 182, which rotates the second annular gear174, which rotates the second drive shaft gear 172, which rotates thesecond drive shaft 88 relative to the rotatable main shaft 74.

In many embodiments, the main shaft coupling fitting 168 includesexternal gear teeth 184 engaged with a main shaft interface 94 (notshown) that is driven by the main shaft motor 90 (not shown.) The mainshaft interface 94 and the main shaft motor 90 can be located on a toolmanipulator 136 (shown in FIG. 8) so as to be coupled with the mainshaft coupling fitting 168 when the proximal tool chassis 134 is mountedon a tool manipulator 136.

FIG. 13 is a perspective view of a cross section of components of theactuation assembly of FIG. 10, illustrating various components and therouting of end effector control cables, in accordance with manyembodiments. The proximal tool chassis 134 includes a base 186 thatprovides a mounting base for various components. The main shaft couplingfitting 168 is mounted to rotate relative to the base 186 via twobearings 188. The main shaft coupling fitting 168 supports the rotatablemain shaft 74. The main shaft 74 has an axial bore through which thefirst drive shaft 86, the second drive shaft 88, and two pairs ofcontrol cables 114 are routed. The first drive shaft 86 and the seconddrive shaft 88 are offset from the centerline of the main shaft couplingfitting 168 and the rotatable main shaft 74, which allows the controlcables 114 to be routed along the centerline of the main shaft. In manyembodiments, rotation of the main shaft relative to the base producestwisting of control cables 114 due to the corresponding rotation of theend effector base relative to the proximal chassis base 186. Routing thecontrol cables 114 along the centerline of the main shaft may help toreduce detrimental impacts to the operation of the control cables thatmay occur in connection with such twisting, for example, by reducingcable to cable frictional forces and/or by reducing associated controlcable stretching.

In many embodiments, a pair of control cables is actuated by a commonactuation mechanism, for example, by a capstan around which the pair ofcontrol cables is wrapped. Such a common actuation mechanism can be usedto retract one control cable of a pair of control cables while the othercontrol cable of the pair is let out by a corresponding amount. FIG. 13illustrates a first capstan 190 for actuating a first control cable pairand a second capstan 192 for actuating a second control cable pair.

In many embodiments, the first drive shaft 86 is rotationally coupledwith a first drive shaft extension 200 via a first splined coupling 194that couples a distal end of the first drive shaft 86 with a proximalend of the first drive shaft extension 200. The first splined coupling194 can be used to enable the use of a conveniently sized first driveshaft 86, for example, so that the first drive shaft 86 can be producedwithout undue expense, and so as to be more easily assembled into theoverall assembly. The first splined coupling 194 can also provide forthe accommodation of a range of axial motion of the first drive shaftextension 200, which, as discussed above, may result during thearticulation of the end effector base relative to the main shaft due tothe first drive shaft extension 200 being offset from the main shaftcenterline. Likewise, a second splined coupling 196 can be used inconnection with the second offset drive shaft 88, and may providesimilar benefits.

FIG. 14 is a cross-sectional view of components of the actuationassembly of FIG. 10, further illustrating various components and therouting of end effector control cables, in accordance with manyembodiments. The internal ring gear teeth of the first annular gear 156interact with the first drive shaft gear 166 so that rotation of thefirst annular gear 156 relative to the main shaft coupling fittingproduces a corresponding rotation of the first drive shaft 86 relativeto the main shaft coupling fitting. The internal ring gear teeth of thesecond annular gear 174 interact with the second drive shaft gear 172 sothat rotation of the second annular gear 174 relative to the main shaftcoupling fitting produces a corresponding rotation of the second driveshaft 88 relative to the main shaft coupling fitting.

FIG. 15A is a perspective view of the main shaft coupling fitting 168,in accordance with many embodiments. The main shaft coupling fitting 168includes a number of openings, slots, fastener holes, as well asexternal gear teeth. A first opening 206 accommodates the protrudinggear teeth of the first drive shaft gear 166. A second opening 208accommodates the protruding gear teeth of the second drive shaft gear172. A third opening 210 accommodates a protruding feature of a driveshaft bearing support fitting used to support the proximal end of thesecond drive shaft. A number of fastener holes 212 are provided thataccommodate drive shaft support bearing mounting fasteners. In manyembodiments, the main shaft coupling fitting 168 includes symmetricalfeatures so as to allow for a reversible installation of the first andsecond drive shafts. The external gear teeth 184 are used to rotate themain shaft coupling fitting 168 relative to the base of the proximaltool chassis. Two slots 214 accommodate the first splined coupling 194and the second splined coupling 196.

FIG. 15B is a perspective view of an internal subassembly that includesthe two internal offset drive shafts and associated support bearingmounting components, in accordance with many embodiments. The firstdrive shaft proximal portion 198 and the second drive shaft proximalportion 202 are received within bearings that are supported by fourinternal support fittings 216. The four internal support fittings 216are held in position within the main shaft coupling fitting 168 via acorresponding four external support fittings 218, which are coupled withthe internal support fittings 216 via two fasteners 220 per fittingpair.

FIGS. 15C and 15D are views showing the combination of the components ofFIGS. 15A and 15B, in accordance with many embodiments. FIG. 15C is aperspective view of the combination and FIG. 15D shows an end view,which shows the fasteners 220, the external gear teeth 184, an externalsupport fitting 218, the first drive shaft gear 166, the second driveshaft gear 172, two internal support fittings 216, and a retainer ring222 used to secure the second drive shaft proximal end relative to aninternal support fitting 216. A central space 224 located betweenadjacent internal support fittings 216 accommodates the routing of thecontrol cables (not shown).

Alternative approaches can be used to support an offset internal driveshaft. For example, FIG. 16 is a perspective view of an actuationassembly 230 having a reduced part count configuration. The actuationassembly 230 provides for the independent actuation of the abovedescribed two offset drive shaft 86, 88, but eliminates some of theabove described components used to support the two offset drive shafts86, 88. The actuation assembly 230 does include some of the abovedescribe components, for example, the first drive shaft 86 (hidden fromview), the second drive shaft 88, the first annular gear 156, and thesecond annular gear 174. The actuation assembly 230 includes a mainshaft coupling fitting 168A that is configured with integrated supportfor the drive shaft support bearings. Similar to the above describedmain shaft coupling fitting 168, the main shaft coupling fitting 168Aincludes external gear teeth 184 for engagement with the above describedmain shaft interface 94 (not shown).

FIG. 17 is a perspective cross-sectional view of the actuation assembly230, illustrating details of the integration of the support for thedrive shaft hearings into the main shaft coupling fitting 168A. The mainshaft coupling fitting 168A is configured with externally accessiblerecesses 232, 234, 236 that interface with first drive shaft supportbearings 164A, 164B and second drive shaft support bearings 170A, 170B.Retainer rings 244, 246 are used to retain the support hearings 164A,164B within the recess 234. Retainer rings 240, 242 are used to retainthe support bearings 170A, 170B within the recess 236. The distallydisposed recess 232 is shaped to accommodate the distal end of the firstdrive shaft 86. The proximally disposed recess 234 is shaped to supportthe proximally disposed support bearings 164A, 164B and to accommodatethe proximal end of the first drive shaft 86. The main shaft couplingfitting 168A includes a bore 238 configured to slidingly receive andaccommodate the first drive shaft 86. The distally disposed recess 236is shaped to support the support bearings 170A, 170B and to accommodatethe second drive shaft 88.

The first drive shaft 86 can be assembled into the actuation assembly230 using the following assembly sequence. First, the support bearing164A is placed in its installed position. The retainer ring 244 is thenmoved from the proximal end of the main shaft coupling fitting 168A intoits installed position. A subassembly comprising the first annular gear156 and the first annular gear bearing 162 is then moved from theproximal end of the main shaft coupling fitting 168A into its installedposition. The first drive shaft 86 is then installed by threading thedistal end of the first drive shaft 86 through the support bearing 164A,and through the bore 238. The support bearing 164B is then slid alongthe recess 234 into its installed position. Finally, the retainer ring246 is then moved from the proximal end of the main shaft couplingfitting 168A into its installed position. A similar sequence can be usedfor the installation of the second drive shaft 88 into the actuationassembly 230.

FIGS. 18A and 18B are proximal and distal end views, respectively, ofthe actuation assembly 230. FIG. 18A shows the proximally locatedsupport bearing 164B relative to the proximal recess 234 and the firstdrive shaft 86. The retainer rings 240, 242, 244, 246 are locally shapedto accommodate the support bearings 170A, 170B, 164A, 164B,respectively. FIG. 18B shows the distal ends of the first drive shaft 86and the second drive shaft 88, the associated recesses 234, 236 in themain shaft coupling fitting 168A, as well as the support bearing 170Adisposed in the recess 236.

FIG. 19 is a plan view illustration of the integration of the actuationassembly 230 within a proximal tool chassis 250, in accordance with manyembodiments. In addition to supporting and actuating the actuationassembly 230, the proximal tool chassis 250 further includes actuationand routing components for three pairs of control cables that are routedwithin the rotatable main shaft.

FIG. 20 is a simplified perspective view diagrammatic illustration of asurgical assembly 260, in accordance with many embodiments. The surgicalassembly 260 includes a proximal actuation mechanism 262, a rotatablemain shaft 264, an end effector 266, and a wrist mechanism 268. The endeffector 266 can include one or more shaft driven mechanisms (e.g., aclamping mechanism, a linear cutting mechanism, a stapling mechanism).The surgical assembly 260 can also include one or more cable actuatedmechanisms, for example, a cable actuation mechanism that articulates abase of the end effector relative to the main shaft via the wristmechanism 268, and/or a cable actuation mechanism that articulates aportion of the end effector relative to the end effector base. Theproximal actuation mechanism 262 can include the above discussedactuation mechanism for the mounting and actuation of one or more offsetdrive shafts routed within the rotatable main shaft 264. The proximalactuation mechanism 262 can be configured for use in a variety ofapplications, for example, as a hand held device with manual and/orautomated actuation for the rotation of the main shaft 264 and/or theone or more internal drive shafts. As such, the surgical assembly 260can have applications beyond minimally invasive robotic surgery, forexample, non-robotic minimally invasive surgery, non-minimally invasiverobotic surgery, non-robotic non-minimally invasive surgery, as well asother applications where the use of one or more offset drive shaftswithin a rotatable outer shaft would be beneficial.

FIG. 21 is a simplified flow diagram of a method 270 for transmittingtorque through an offset drive shaft routed within a rotatable mainshaft, in accordance with many embodiments. In step 272, a main shaft issupported to rotate relative to a base. In step 274, a drive shaft issupported to rotate relative to the main shaft about a drive shaftrotational axis that is offset from the main shaft rotational axis. Instep 276, the offset drive shaft is engaged with a drive feature havinga rotational axis that is fixed relative to the base. In step 278, themain shaft is rotated relative to the base. In step 280, the drive shaftis rotated relative to the main shaft by rotating the drive featurerelative to the main shaft. The steps of method 270 can be accomplished,for example, using the embodiments discussed above with respect to FIG.6 through FIG. 19.

FIG. 22 is a simplified flow diagram of a minimally invasive surgicalmethod 290, in accordance with many embodiments. In step 292, an endeffector of a surgical tool is introduced to a surgical site, forexample, an internal surgical site via a minimally invasive aperture ornatural body orifice. The end effector is mounted to a distal end of anelongated instrument shaft mounted to rotate relative to a base so thatthe end effector can be rotated with the instrument shaft relative tothe base. The end effector is operatively coupled with a first driveshaft so that rotating the first drive shaft relative to the instrumentshaft actuates an end effector first mechanism, the first drive shaftbeing mounted to rotate relative to the instrument shaft about a firstdrive shaft rotational axis that is offset from the instrument shaftrotational axis. In step 294, the end effector is rotated by rotatingthe instrument shaft. In step 296, a surgical task is performed with theend effector by actuating the end effector first mechanism.

In many embodiments, the method 290 involves the use of an end effectorthat is actuated by two drive shafts. A wide range of end effectormechanisms can be drive shaft actuated. For example, the end effectorcan include a clamping feature actuated by the first drive shaft. Theend effector can include a movable cutting feature actuated by thesecond drive shaft. The surgical task can include clamping tissue withthe clamping feature and cutting tissue with the movable cuttingfeature. The second drive shaft can be mounted to rotate relative to theinstrument shaft about a second drive shaft rotational axis that isoffset from the instrument shaft rotational axis. The end effector caninclude a cutting and stapling device actuated by the second driveshaft. The surgical task can include clamping tissue with the clampingfeature, stapling tissue with the cutting and stapling device, andcutting tissue with the cutting and stapling device.

It is understood that the examples and embodiments described herein arefor illustrative purposes and that various modifications or changes inlight thereof will be suggested to persons skilled in the art and are tobe included within the spirit and purview of this application and thescope of the appended claims. Numerous different combinations arepossible, and such combinations are considered to be part of the presentinvention.

What is claimed is:
 1. A robotic assembly, comprising: a base; a mainshaft mounted to the base to rotate relative to the base and comprisinga proximal end, a distal end, and a main shaft rotational axis definedtherebetween; a drive shaft mounted inside the main shaft and offsetfrom the main shaft rotational axis; an actuation assembly drivinglycoupled with the main shaft and the drive shaft, the actuation assemblyoperable to independently rotate the main shaft relative to the base,and rotate the drive shaft relative to the main shaft; an end effectorcoupled with the main shaft, the end effector comprising a shaft drivenactuation mechanism coupled with the drive shaft.
 2. The assembly ofclaim 1, further comprising a second drive shaft mounted inside the mainshaft and offset from the main shaft rotational axis, wherein theactuation assembly is further operable to independently rotate thesecond drive shaft relative to the main shaft, and wherein the endeffector further comprises a second shaft driven actuation mechanismcoupled with the second drive shaft.
 3. The assembly of claim 1, furthercomprising a control cable coupled with the end effector, the controlcable routed within the main shaft between the main shaft proximal anddistal ends, wherein a motion of the control cable actuates the endeffector.
 4. A robotic system, comprising: a base; a main shaft mountedto rotate relative to the base and comprising a proximal end, a distalend, and a main shaft rotational axis defined therebetween; a firstdrive shaft mounted inside the main shaft and offset from the main shaftrotational axis; a second drive shaft mounted inside the main shaft andoffset from the main shaft rotational axis; an actuation assemblycoupled with the main shaft, the first drive shaft, and the second driveshaft; a controller comprising an input and an output, the input coupledwith an input device to receive at least one input signal from the inputdevice, the output coupled with the actuation assembly to output atleast one control signal to the actuation assembly, the controllercomprising a processor and a tangible medium containing instructionsthat when executed cause the processor to generate the at least onecontrol signal in response to the at least one input signal so that theinput device can be used by a user to independently rotate the mainshaft relative to the base, rotate the first drive shaft relative to themain shaft, and rotate the second drive shaft relative to the mainshaft; and an end effector coupled with the main shaft so that the endeffector is rotated by a rotation of the main shaft, the end effectorcomprising a first shaft driven actuation mechanism coupled with thefirst drive shaft, and a second shaft driven actuation mechanism coupledwith the second drive shaft.
 5. The system of claim 4, wherein theactuation assembly comprises: a first motor coupled with the first driveshaft and the controller; a second motor coupled with the second driveshaft and the controller; and a main shaft motor coupled with the mainshaft and the controller.
 6. The system of claim 5, wherein theactuation assembly further comprises: a first encoder coupled with thefirst motor and the controller, the first encoder outputting a firstmotor position signal to the controller in response to a position of thefirst motor; a second encoder coupled with the second motor and thecontroller, the second encoder outputting a second motor position signalto the controller in response to a position of the second motor; and amain shaft encoder coupled with the main shaft motor and the controller,the main shaft encoder outputting a main shaft position signal to thecontroller in response to a position of the main shaft motor.
 7. Thesystem of claim 4, further comprising a control cable coupled with theend effector, the control cable routed within the main shaft between themain shaft proximal and distal ends, wherein a motion of the controlcable actuates the end effector.
 8. A robotic tool for mounting on amanipulator having a tool interface with first, second, and third drivefeatures, the tool comprising: a proximal tool chassis releasablymountable to the tool interface; a distal end effector having a distaldegree of freedom and a shaft driven actuation mechanism; a main shafthaving a proximal end adjacent the chassis, a distal end adjacent theend effector, a bore extending therebetween, and a lateral openingdistally of the proximal end; and a hybrid cable/shaft drive systemincluding: a first input coupler configured to drivingly couple to thefirst drive feature when the chassis is mounted to the tool interface,the first input coupler being drivingly coupled with the main shaft sothat actuation of the first input coupler rotates the main shaft and theend effector relative to the chassis about a main shaft rotational axis,a second input coupler configured to drivingly couple to the seconddrive feature when the chassis is mounted to the tool interface, thesecond input coupler being drivingly coupled with the end effector sothat actuation of the second input coupler articulates the end effectorrelative to the distal degree of freedom; and a third input couplerconfigured to drivingly couple to the third drive feature when thechassis is mounted to the tool interface, the third input coupler beingdrivingly coupled with first drive shaft via an intervening drivecomponent that extends through the lateral opening in the main shaft,the first drive shaft being offset from the main shaft rotational axisand drivingly coupled with the shaft driven actuation mechanism.